It is well known that the accumulation of a great amount of a biomass on the surface of offshore installations, platforms and piles, as well as on ships' bottoms, causes serious biological problems and causes substantial damage. One effective way to protect various surfaces against marine fouling is the use of chemicals, namely, the application of protective polymer coatings containing antifouling agents.
An important stage in solving the fouling problem is the search for more effective antifouling agents. Organotin compounds are known to be widely employed as antifouling toxins in various polymer coatings.
The prior art antifouling polymer compositions contain, as the active component, organotin carboxylate compounds of the general formula R--COOSn(n--C.sub.4 H.sub.9).sub.3 (wherein R is an alkyl, aryl), CCl.dbd.CCl--COOSnR.sub.3 (wherein R is an alkyl), (cf. Japanese Patent Nos. 1,103, 1909, Cl. 24F1; 26,437, 1970, Cl. 24F1; 31,553, 1970, Cl. 24F1).
There has been proposed an antifouling composition with organotin toxins of the R.sub.3 SnX type (wherein R is an alkyl, aryl; X is a halogen) (cf. Japanese Patent No. 26,438, 1970, Cl. 24F2).
The "Takeda Chemical Ind. Ltd" compound has developed an antifouling polymeric paint containing, as the toxin, a synergistic mixture of aminochloronaphthoquinone, Cu.sub.2 O and hexabutyldistannoxane [(n-C.sub.4 H.sub.9).sub.3 Sn].sub.2 O or trialkylfluorostannane R.sub.3 SnF and bis-trialkylstannylmaleate R.sub.3 SnOOC--CH.dbd.CH--COOSnR.sub.3 (cf. U.S. Pat. No. 3,615,744; Cl. 106/15 CO9d5/14; 1971).
The "Plastic Molders Supply Inc" compound has proposed a composition for protecting ships' bottoms and offshore installations against fouling, based on a polyester resin and an organotin compound (12-20%) of the R.sub.3 SnF type, wherein R is an alkyl, aryl (cf. French Pat. No. 2,055,996; Cl. CO9d5/00 1971).
To impart antifouling properties to paints, the "Caddsec Chemical Works Inc." company of the United States has proposed a composition containing organotin sulfur-containing compounds of the general formula [R.sub.3 SnOOC(CH.sub.2).sub.n S].sub.2 CH.sub.2, wherein R is an alkyl (cf. U.S. Pat. No. 3,463,644; Cl. 106-15 (A61k); 1960).
A patent has been granted for a polymer material for an underwater antifouling coating, which contains high-molecular organotin compounds obtained by full or partial introduction of compounds of trialkyl(phenyl)tin, amines, isocyanates, etc. into the carboxyls of a dimeric acid (cf. Japanese Pat. No. 1,224/73; Cl. 24F21 (COd5/16), 1973).
Also proposed as antifouling agents have been organotin compounds of the (n-C.sub.4 H.sub.9).sub.3 SnXR type (wherein R is a halogenated phenyl, X=O,S) (cf. Japanese Pat. No. 48-41,258; Cl. 24F1, 1973) and of the (n-C.sub.4 H.sub.9).sub.3 SnX type (wherein X is toluene sulfoanilide) (cf. Japanese Pat. No. 37,491; Cl. 24f2, 1972).
There has been proposed a method for producing biostable paints and varnishes by way of modification of known polymers with organotin methacrylates, maleates and their polymers in combination with a binder, a filler, a solvent and other additives (cf. USSR Inventor's Certificate No. 210,296; Cl. 22h 10/01, 39b, 22/01 (CO9d, CO8f), 1967).
Also known are antifouling paints based on bis-(triphenyl-tin)-monochloromaleinate (C.sub.6 H.sub.5).sub.3 SnOOC--CH.dbd.CCl--COOSn(C.sub.6 H.sub.5).sub.3 (cf. Japanese Patent No. 51-41,648, 1976), compounds of the (C.sub.6 H.sub.5).sub.3 SnX type, wherein X=OH, F, Cl, OOCCH.sub.3, OOCCH.sub.2 Cl, OSn(C.sub.6 H.sub.5).sub.3 or compounds of the formula (C.sub.6 H.sub.5).sub.3 SnOOC-CH(Br)COOSn(C.sub.6 H.sub.5).sub.3 (cf. Japanese Pat. No. 51-109,934, 1976).
The above prior art organotin compounds used as antifouling agents suffer from a number of serious disadvantages, namely;
The process of producing these compounds is complex and involves numerous steps. Raw materials are scarce or unavailable.
Most organotin compounds are powders or solids with a pungent odor, which necessitates additional expenses and precautions when they are introduced into paints.
Organotin and chlororganic compounds are, when taken separately, less effective toxins against marine fouling. Halogen-containing agents suppress growth of organisms primarily of vegetal origin, while organotin toxins prevent accumulation of a biomass predominantly of animal origin.
The prior art organotin compounds are highly effective as antifouling agents, however their activity is short lived because of the high rate of their leaching out in sea water.
The prior art compounds are poorly soluble and compatible with known film-forming polymers, pigments and fillers used in antifouling coatings.
The prior art antifouling coatings with the above organotin compounds are not adequately adhesive and strong, and their weatherproof characteristics are poor.